Full-back O'Connor sustained the injury in the midweek win over Norwich but is hoping to start again, while manager Sean O'Driscoll has no new injury or suspension worries.
Rovers turned in arguably their best display of the season on Tuesday and O'Driscoll must decide whether to recall skipper Brian Stock to the starting line-up. James Coppinger struck a hat-trick against Norwich and is expected to start alongside Billy Sharp up front while Martin Woods, Simon Gillett, Mark Wilson and John Oster will be hoping to continue in midfield.
O'Driscoll's side, still without Byron Webster (foot), James Chambers and Wayne Thomas (both knee) and James Hayter (hamstring), can move into second place with a third successive home win.
Leeds manager Simon Grayson is expected to make several changes. Grayson's side travel to take on one of their local rivals for the second successive match following the 5-2 midweek defeat at Barnsley and the Elland Road boss has promised to shake things up.
Robert Snodgrass (knee) and Billy Paynter (shin) could be ready to return after completing a full 90 minutes in a recent behind-closed-doors friendly. Neither player has appeared this season.
Latest signing Ramon Nunez scored in the same match and is pushing for his debut while another striker, Davide Somma, was on target after stepping off the substitutes' bench again at Barnsley and could be handed his first start for the club.
Forward Ross McCormack, midfielder Adam Clayton, winger Sanchez Watt and defender Alex Bruce all started on the bench at Oakwell and will also come into the reckoning.